Ref the park brake prober. Not any more.
There's an SB (mandatory I think) which puts additional switches in the circuit to ensure the park brake is really set.
Back in the day this was the case and all you had to do was pull the park brake handle to illuminate the park brake light.
Now the pedals need to be latched into the PB cam to illuminate the light. The only way it won't be set is if the brakes are set without hydraulic or accumulator pressure (or it was set and the brake pressure has depleted over a period of time).